Pathological demand avoidance

Hi, I am completely new to this but am desperately looking for guidance!

I have a twenty year old son who on reflection has been struggling for years but has hidden his difficulties.

During sixth form college things deteriorated. It didn’t help that he started in September 2020 and due to lockdowns and self isolating there was a lack of continuity and routine. He started to miss college, telling us his teacher was self isolating and telling college he had an  appointment. At this time I also noticed how painfully thin he was. He had always been very slim, then had a huge growth spurt, but never put the weight on. His eating had become disordered. He still had three meals a day, typically eating the same breakfast and lunch each day. The evening meal would vary and he became noticeably pickier about what he would eat. (He has been fussy as a small child but not to the extent it caused concern.) He would eat painfully small amounts but we would then discover copious amounts of empty packets and wrappers of sugary foods in his room. When he sat at the table with us he always appeared on edge, wound up. If anyone spoke to him they would be snarled at. His siblings eventually stopped talking to him and still don’t talk with him now.

I contacted the GP about his weight and his eating habits. The GP asked me what I expected them to do! I asked for a dietician referral which happened and my son was monitored by them for a time.

I referred him to CAMHS as his mood and self esteem seemed to be so low, he was refusing college and I was concerned there could be some sort of eating disorder. They sent him some leaflets. He didn’t follow anything up.

He started work after college, working night shifts, so we saw less and less of him. Last summer though, it was clear things were not well. He ended up stopping work and having a breakdown.

It took time for him to actually be able to see a doctor (there were telephone calls, online assessments etc before). Since January he has been on medication for anxiety and depression, has been having therapy and has been under the mental health team. He is also waiting for an autism assessment.

He says he feels less stressed but otherwise seems no better to us. He spends all day in his room, with the blinds down (he does go out to his appointments). He rarely showers. He hasn’t had any sheets on his bed for at least a month. He games until the early hours of the morning (he says that’s when his friends are online and also that he can’t sleep anyway). He then sleeps in, sometimes until we’ll into the afternoon.

Today I asked if I could speak with him - that things do need to change. He has spoken about having pathological demand avoidance and me asking him to do something is unlikely to have the desired effect. I have looked for guidance online but find things aimed at children such as making a game out of things. I don’t see this working with a twenty year old. So please, if anyone can advise or direct me to resources that can help my son to start looking after himself I would be very grateful.